Apparatus for indicating the mean speed of a. vehicle



ARCH mom FERENCE muss R MEAN SPEED of A VEHICLE Fed 1929 2 Sheets-Sheet l TTU/WYE VJ.

Dec. 6, 1932. E. PELLI-:RIN ET AL y 1,389,875 V APPARATUS FOR INDICATING THE MEAN SPEED 0F A VHICLE t Filed Jan. 22. 192s 2 sheets-.sneer '2 Arron/vers.'

resented Dee. e, 1932 UNITED STATES PATENT" OFI-Ica v PELLEBIN, MARCEL HECTOR, AND PASCAL JULES CARPENTIER, OY

f VINCENNES, FRANCE .PPABATUS'IOR INIDICA'JIINGV THE MEAN' SPEED 0F L VEHICLE y' appunti@ mea January 22, 192s, serial 11. 334,296, ma in France January a4, 192s'.

I The present invention relatesto an appaf ratus which permits to measure, by a logarithmic transformation, the mean speed of a. vehicle at a given time after 'the start or I the zero point.

that is, log v==log e-log t.

The distance covered e is given at each instant by .the mileage counter and the time by the time-piece or clockwork mounted on the vehicle.' In. this case, if logarithmic cams are mounted on the shaft of the hands of the said time-piece and on the shaft of the mileage register, the'rollers cooperating with said cams will be displaced by quantities which are respectively proportional to the logarithms of the distance and of the time. If the rods carrying the said rollers are placed in relation with a systemo a mechanical, hy-

draulic, electric, or like nature, permitting the diierence between the displacements of the said rods to be obtained, that is, the difference between the logarithms of the distance and the time, and it' this system is combined'with a suitable device for transformation or restitution, the speed 'v will be finally.

obtained.

.The followingdescription with reference y3&'5 to the accompanying drawings which is given by Way of example shows the manner in phich the said invention is carried into eect.

Figure 1 is a diagrammatic view of the 40 first embodiment of the invention, showing the general principle upon which the invention is based. l Figure 2 is a diagrammatic view showing the principle employed in the second embodiment. Figure 3 isa front view of the apparatus lon the side of the dial, with parts of the said dial broken away to show the interior of the mechanism.

:l Figure 4 is a section on the line 4 4' of Figure 3, viewed in vthe direction of the arrow.' f i 'Figure 5 is a diagrammatic general view -with reversal on the plane of the figure, of

the part situated to the left of the line 5--5 55 v of Figure 4, showing the details of the internal arrangements of the different parts ofthe apparatus.

f Figures 6 and 7 relate to a particular form of construction of the logarithmic cams.

As shown in Figure 1, 1 is the logarithmic cam which is actuated by the mileage counter, and it is in contact with the rod 3b which is longitudinally displaced by a quantity proj portional to the logarithm v01E the distance. 05 In like manner, 2 is the logarithmic cam which is actuated .by the clockwork which acts upon the rod 41,. The said cams 1b and 2b are herein constituted bya rotating cylinder c in which is formed a helical line or groove whose pitch varies according to a log-` arithmic law, andthe rods 3b and 41, are provided with the pointed 'ends e which are guided by the lines or grooves of cams 1b and 2b respectively. The rods 3b and 4b are con- 75 nected respectively to the pistons p1 and p2 in the cylinder C containing liquid, and the said cylinder C includes a. third piston p3 which is displaced by a quantity proportional to the sum or dierence of the displace- 50 ments of p1 and p2 according to the relative direction of the said displacements.

The piston rod ps carries a rack 17 engaging the gear wheel 18 secured to an indicat ing pointer 19 cooperating with a dial 20. 85 It the said dial is suitably graduated, a simple readingv will show the number of which the displacement of p represents the logarithm, that is, the mean speed. 9

The transmission by the liquid, obtained as shown in Figure 1, is very simple, and it illustrates the general principle of the invention. It 'is evident that the number of logarithms whose algebraic sum may be obtained, that is, the number of factors of the initial product, is not limited, for the cylinder C may contain as many pistons as desired, thesebeing actuated by the logarithmic cams.

Irithe modications shwn in Figures 2 to 190 5, the power transmission is exclusively of a mechanical nature..

In .Figure 2, showing the principle employed, 1l is the logarithmic cam tor the distance, actuated by the mileage counter K through the medium of the set of shafts and gearing 38-46. The cam 2a is the logarithmic camof the time which is actuated by the clockwork M by means of the set ot' shafts and gearing 21 to 36. The cams 1,L and 2l are .in contact with the lrods 3 and 4, urged by the springs 31 and 41, and said rods comprise at thelr ends opposite the cams, the racks 5 and 7 which engage kthe double-toothed pinions 8 and 9 of the differential D. In this manner the rotation oi 8 and 9 is respectively pro-` the radius vector and v the angle. The rod.

16 which is held in contact with the cam 15 by the spring 16 carries a rack 17 engaging a pinion 18 secured to the` indicating pointer 19 which gives the mean speed at the moment yin question, upon the dial 20.'

Figures 3 and 4 show a practical arrangement of the system represented in Figure 2, the mechanism being contained in the cylindrical casing S. f

The logarithmic cams '1 and 2 consist in this second embodiment of a surface having the shape of a rustrum of cone upon which is formed a. helical contact surface adapted to cooperate with the ends of rods 3 and 4 which, when projected parallel with the axis of rotation of the cam, forms a logarithmic s iral.Y Otherwise stated, the said cams are o tained by the intersection of a truncated cone with a coaxial cylinder whose directrix is a logarithmic spiral or a curve ot which the equation, when polar coordinates are used, is: r=a log o; 9" being the radius vector and 'v the angle.

As rods 3 and4 can only slide parallely to their longitudinal'direction, the central apertures of the cams 1 and 2 as well as their respective rods 37 and 47 are screw threaded so as to cause said cams, when rotating, to move longitudinally along said threaded rods, the pitch of the threads being equal to the width of the contact surface, so that durino' the forward motion of the cams along ro 7 and 47, rods 3 and 4 may be continuously applied against said Contact surface. V

' In their rotation on their axes, the said and. 21 which are situated in their interior and which serve to bring thesaid cams to their starting lposition when they attain the end of their stroke, due tothe release of the electromagnetic device, as will he further speciiied. The vtwo spiral springs 11 and 21, which springs serve to bring the apparatus to zero have their ends secured on the one hand to the cams 1 and 2 and on the other hand to the machine frame, and when the said cams rotate, the said springs are twisted and stretched.

The said cams also carry external teeth i 36-46 engaging the pinions 35 and 45 which are respectively driven by the clockwork and bythe mileage counter, and which rotate the said cams. The length of the teeth of the pinions and 45 must be such that the teeth 36 and 46 remain constantly engaofedwith the said pinions in spite of the displacement vof the said cams on their shafts.

The diagram shown in Figure 5, which is obtained by sectioning the Figure 4 on the line 5--5 and by reversing upon the plane of the figure the part situated to the left of 'f5-5, represents the electric connections by which the said cams are brought into the starting position, that is, by which they are returned to zero when at the end of thestroke, or even at any time desired by the driver.

- The clockwork M rotates the cam 2 by means of the shaft 21, the clutch .Q4-25, the shaft 2 the clutch 304-31, the shaft 23, the pinions 32 and 33, the shaft 34. the pinion 35 and the toothed portion 36. In like manner, the mileage counter K rotates the cam l by means of the shaft 38, the clutch 39-49, the shaft 41, the pinions 4243, theshaft 44. the pinion 45 (these two latter parts are not shown in Figures 4 and 5 but are `shown in Figure 3) and the teeth 46.

The movable toothed ring 30 of the clutch 30-31 connecting together the shafts 22 and 23 is keyed to' the shaft 22 in such manner as to separate it from the ringv 31, the toothed ring 39 of the clutch 239-40 being mounted in like manner'on the shaft 38. The two movable toothed rings are connected together by a bar 49 which holds them in engagement under the action of the springs 50--51-52. Adjacent the bar 49 is mounted an electromagnet 53 supplied by a storage .battery 54 by means of the movable rods 57-59 provided with the studs 571---572 and 591-592, and with the fixed contacts 58 and 60. Said contacts 58 and 60, as well as the rods 57 and 59 must be insulated from the casing of the apparatus.

r.lVhen either of the cams land 2 reaches the ,end-of its dis lacement along rods 47 or 37 respectively, t at cam engages stud 592 er 572 respectively, which brings the corresponding rod 59 or 57 into contact with 60 or 58 respectively, and closes the electric circuit. "Electro-magnet 53 is energized. and

'il frei* attracts baratti, thusuncoupling both clutches 30-31 and 39-40, so that the cams which are i disconnected from the clockworkandthemileage counter respectively are returned to their initial positions under the action of the spiral springs 11 and 21. At this time, the Vcams make contact with the studs 571 and 591, thus breaking the circuit of the electrofmagnet and again coupling clutches 30-31 and 39,-40 res ectively. This return of the cams to zero which takes place automatically at the end of the longitudinal movement of either of the cams may also be edected by hand at any time yby means of the switch 55.

The said apparatus provides for the meas-r urement of two mean 'speeds,rthat is, the mean speed of operating or the mean speed calculated with deduction of the time of stopping o the vehicle, and the mean commercial speed in which the said stopping times are included. The driver will always be able to change from one of these speeds to the other,

by uncoupling the clockwork or by leaving it coupled during the stops, due to the device y 'which will be further described. 'The' two shafts 21 and 22 are connected together by a coupling which consists of the toothed rings 24 and 25, the ring 24 being keyedon the shaft 21 and the ring 25 vkeyed to the shaft 22. The' said ring 25 is secured to a toothed wheeler aratch'et wheel flenga ing a pawl 261. A disk 27,iixed lto said rato et wheel is subjected to the action of a spring 28, which normally acts against the uncoupling.

An electromagnet 29 disposed opposite the,

disk 27, may at any time uncouple the movable ring 25, that is, it may release the cam 2 from the action of the clockwork, while maintaining it in the position acquired due to the action of the pawl 261 which does not permit the expansion of the spring 21 of the cam 2. The circuit of the electromagnet 29 comprises the manually controlled switch 56.

and a switch 61 which is automatically closed when the vehicle stops. This switch 61 is formed, for example, by the pointer 6l of the ordinary speed indicator of the vehicle,

which pointer abuts against the contactvllf when the vehicle stops. VTo obtain the comm'ercialspeed, the driver, leaves the switch 56 open, thus preventing in all cases the closing Aof the circuit of theelectromagnet 29, and

hence leaving the clockwork constantly coupled. On the contrary, to obtain the speed of travel, the driver closes the switch 56, and when the vehicle stops, the pointer 6l closes the circuit and the clockwork remains uncoupled during the whole period of the stop.

It is evident that the arrangement described is susceptible of numerous modifications in detail without departing from the spirit of the invention.

Thus for instance in the second form of construction, the logarithmic cams, instead of being tapered, may consist as in thecase said pointer.

of Fi rel of a'cylinder 62 on which is forme( a groove (Figures 6 and 7) according "to a helical line 63 whose pitch varies according to a logarithmic law, and thus the point 64 of the slide 65 mounted on the rod 3 or 4 land guided by the said'line and by the rails 66, will thus be given a displacement proportional to the logarithm of the angular rotation of the cylinder. e

It is evident that ythe, different elements forming part ofthe saidV apparatus may be used separately upon other apparatus than the aforesaid mean speed indicators.

For example, the logarithmic cams may be employed with meters, calculating machines andthe like, and in general with all apparatus adapted to forni a product or a quotient of variable quantities.

The zero return device, which is electrically operated in the present apparatus, but which -may be operated exclusively by mechanical means, is susceptible of numerous uses upon indicating or recording apparatus of all kinds. f

VS7-hat we claim is:

l. An apparatus of the type described comprising in combination a casing, two threaded rods-mounted in said casing, two

Vconoidal spirally grooved logarithmic cams adapted to screw on said rods respectively, two toothed wheels integral with said cams, a toothed drum adapted to mesh with the Vtoothed wheel of the first cam, an odometer, means for driving said drum from said odometer, another toothed drum adapted to mesh with the toothed wheel of the second cam, a watch, means for driving said last mentioned ,drum from said watch, two rods slidably -with the toothed wheel of the second cam, a

watch, means for driving said last mentioned drum from said watch, two rods slidably actuated by said cams respectively, an indieating pointer, a sun and planet gear for actuating said pointer, and a rack on each of said slidable rods adapted to drive each of the sunvvwheels ot said gear respectively.

' 3. An apparatus of the type described coinpiising in combination, two cams, two followers, one for each of said cams respectively, a diierential mechanism for combining the movements of said followers, an odometer, transmission means for driving one of p the cams from said odometer, a Watch, transj mission means for driving the other cam from said watch, a clutch in each of said transmission means, a rigid member connecting the movable elements of said clutches whereby they are simultaneously operated, an electromagnet for actuating said rigid member, contacting meansy operated by said cams for closing the circuit of said electro-magnet as soon as one of the cams has completed its rotation, resilient means for resetting the cams adapted to operate when the clutches are disengaged, another clutchin the transmission means between the watch and the corresponding cam, an electro-magnet for operating said last mentioned clutch,' a speedometer, an electric circuit for energizing said electro-magnet, vsaid circuit including the pointer of said speedometer and a contact stud corresponding to the position of said pointer when the speed of the vehicle is zero, whereby said last mentioned clutch Vis auto- A matically disengaged when the vehicle is stopped.

In testimony whereof we have signed this le are 

